Impregnated fabric and process of making the same



Aug. 14, 1928; 1,680,497

H. E. BROWN ET AL IIPREGNATED FABRIC AND PROCESS OF MAKING THE SAIEFiled Sept. 7, 1922 2 Sheets-Sheet 1 H. E. BROWN ET AL IIPREGNATEDFABRIC AND PROCESS OF MAKING THE SAIB Filed Sept. 7. 1922 2 Sheets-Sheet2 Patented Aug. 14, 1928.

UNITED STATES 1,680,497 PATENT OFFICE.-

' HERMAN E. nnowN, or KINGSTON, NEW YORK, m IormaN norms mom or NUTLEY,NEw JERSEY, ASSIGNOBS, BY mEsNE asammms, 1:0 mm nm, or PROVIDENCE, RHODEISLAND, a CORPORATION 0E mom: IsLaNn.

IMPREGNATED FABRIC AND PROCESS OF MAKING THE SAME.

Application filed September 7, 1922. Serial No. name Our inventiom whichis a continuation in part of application No. 493,526, filed Aug. 19,1921, consists in the novel features hereinafter described, referencebeing had to the accompanying drawings, which illustratediagrammatically a form of apparatus wh ch may be advantageouslyemployed in carry ng our process into effect, and the said 1nvention isfully disclosed in the following description and claims.

The object of our Invention 1s to treat a fibrous fabric in which thefibres ex st in a more or less loosely'associated relation, the fibresbeing preferably unspun, unwoven natural fibres arranged in aflat form,as cotton batting, for example, or 1n a felted condition, as in cottonfelt, for example, with a binding material, preferably waterproof andpreferably a rubber compound, in the form of a semi-solid, that is tosay, a dough br putty like form and plastic at the time of application,as distinguished from a socalled solution in which the binding materialis dispersed in a more or less volatile liquid, and as distinguishedfrom a material in a fluid or molten condition, and to mechanicallyforce, by the application of pressure under the proper conditions oftemperature, the said binding material uniformly into the fabric so asto coat the individual fibres throughout the entire fabric withoutcompletely filling the interfibre spaces, and uniting the fibres of thefabric by the cohesion of their individual coatings at points of contactand intersection, and in some instances by additional bonds from onefibre coatin to another so as to produce a resulting'fa ric which, whendried, cured or vulcanized, closely resembles leather, and is suitablefor many of the purposes-for which leather is used. Where the bindingma.-

terial is a rubber composition and is there after properly vulcanized toconvert it from the plastic to the elastic form, the resulting fabricpossesses elasticity in all directions,

due to both the elastic quality of the binding material, which unitesthe fibres ieldingly at their points of intersection an bonding contact,and the .fact that the interfibre spaces are not completely filled,which permits relative .movement of the fibres with respect to eachother, and contributes to the elasticity of the fabric as ordinarilyproduced. The resulting fabric is, pervlou's to air and dry gases, byreason of the minute 6'5 unfilled spaces between the fibre coatings,while it is practically impervious to water, owing to the fact thatthese interfibre spaces are so minute and the repellent action of thebinding material is such, that water does not pass through in theabsence of, pressure, and the fabric will not materially absorb water,as the coating of the individual fibres prevents the penetration ofwater thereinto.

We are aware that attempts have been made 55 to treat the, fibrousmaterial by the application thereto of binding material in iquid form.Where a liquid mixture is employed,

the amount of liquid solvent or dis rsing agent 1s from ten to twenttimes t e bulk of the rubber or other binding material dissolved ordispersed therein. .Even if the fabric is thoroughly pepetrated by sucha liquid, the drying out or evaporation of the liquid would leave notmore than from five to ten per cent of the absorbed liquid, as solidmatter (rubber for example) distrib-' uted among the fibres of thefabric, too little to effect either the coating of the fibres,

or the adequate binding of them together. 89

As a matter of fact, the amount of binding material left in the fabricis even lessthan would be expected, as rubber for example has a greatercohesion than adhesion and where a fabric has been treated with a liquidrubber mixture and subjected to drying action, the li uid mixture withinthe fabric flows from t e interior of the fabric toward the exterior indrying, thus. actually withdrawing the solution or mixture, as a mix- 90ture, and including both the solvent and the dis ersed rubber from theinterior to the exterror of the fabric in a manner somewhat similar tothat resulting where a porous material, such as a brick, is saturatedwith a solution of a chemical solid and on drying the brick the driedsolid is deposited, largely, if not entirely, at or upon the exteriorsurface of the-brick. We have found it to be a fact, by microscopicexaminations, that where fibrous material of appreciable thick- .ness istreated withsuch liquid mixture central portion of the fibres being ebinding material. Where any rubber or other binding material is leftamong interior fibres, it tends to collect in minute globules, and owingto itscohesion, it draws itself together and away from the fibres,leaving the interior fibres naked and uncoated. Where the fibres crosseach other or'come in contact, they do not adhere to each other and arenot united or bound together. Where they cross each other, a sharp lineof crossing is noted under the microscope showing the bare fibresunattached. Moreover where fibrous material is treated by the liquidprocess it is extremely difficult if not impossible to carry materialsinsoluble in the dispersing liquid, such as oxide of zinc, whiting,magnesium oxide, sulphur coloring compounds, etc., into the interior ofthe fabric, as the fibrous material of the fabric acts in the samemanner as a filter cloth in a filter press, to hold back such solidinsoluble matters and prevent them from passing through into the fabric,

' thus leaving them on the outer surface.

In some instances it has been proposed to wring out or squeeze a liquidtreated fabric between rollers or otherwise, but it will readily be seenthat as this squeezing treatment removes a large percentage of the liq-'uid mixture which has penetrated into the fabric, the resulting amountof solid binding material left in the fabric when it is dried, scorrespondingly reduced, and in fact is extremely minute. In accordancewith our invention, we take a fibrous material, preferably composed ofunspun, unwoven fibres, such as cotton felt, cotton batting and thelike, for example, or any material made from natural fibres, and treatthe same with binding material, preferably rubber compounds or plasticcompositions, for example, in a semi-solid form, that is to say in adough like or putty like mass of such composition and consistency, andplastie at the time of application, as to be capable of penetrating intothe interfibre spaces of the fabric, and uniformly coating the fibresthereof, without filling completely the interfibre spaces, and leavingthe fibres coated at their points of intersection and contact by thecohesion of the individual fibre coatings, and in some instancesconnected by additional bonds of the binding material between the fibrecoatings. The material is preferably and ordinarily applied by theapplication of pressure, and preferably between calender rollers, thetemperature and relative speeds of which are maintained in such amanner, according to the composition of the binding material em- Eloyedas to effect the stated result. The

bres as they pass between the calender rolls are compressed beyond apoint at which they will be held in position by the plastic semisolidbinding material in its then condition, forced into the fabric, and onthe release of pressure, the fibres, by their inherent elasticity, tendto expand slightly and rearrange themselves, so as to form minuteinterfibre spaces, unfilled by the binding material, which is later setby the drying, curing or vulcanization of the resulting fabric.

We believe that we are the first in the history of the art to impregnatea non-woven material composed of unspun non-twisted and non-woven fibresby forcing thereinto a binding material in semi-solid condition, plasticat the time of application, and we believe that we are the first toaccomplish this result by means of calendcr rolls.

Referring to the accompanying drawings, Fig. 1 is a form of apparatuswhich may be convenienttliy employed in carrying our process into e ect.

Fig. 2 is a diagrammatic view illustrating a form of apparatus which maybe conveniently employed where the fabric is treated first from one sideand then from the other, with or without afinal rolling to insure bothsides of the fabric being smooth.

Fig. 3 is a diagrammatic sectional view illustrating the effect of theprocess on the fabric where the binding material is forced entirelythrough the fabric, leaving one surface of the fabric in a slightlyroughened condition with upstanding coated fibres to serve as bonds foran exterior coating.

Fig. 4 is a similar view to Fig. 3 illustrating the effect on the fabricwhere the binding material is applied to one face and forced partly butnot entirely through the fabric,

Fi 5 is a view similar to Fig. 3 illustrating t e completed fabric aftera subsequent rolling operation, to smooth down the roughened surface andupstanding fibres left by a preceding application of the bindingmaterial.

Fig. 6 is a view greatly magnified illustrating actual fibres from theinterior of the fabric as they appear under the microscope andillustrating more or less graphically the fibre coatings connected attheir points of intersection and contact and additional bonds of thebinding material connecting the fibre coatings.

As illustrative of our improved process, the following example is givenof a specific binding material, and the specific manner in which it is aplied to produce our improved fabric. in this example, we use acomposition consisting of 250'parts of washed and dried guayule rubber,

250 parts of smoked rubber sheets,

450 parts of zinc oxide,

. 25 parts of washed and dried flowers of sulphur,

15 parts of mono-chloro-naphthaline.

In preparing this compound the smoked sheets are first broken down ormacerated on a mixing mill, as regularly employed in the rubberindustry, by milling until the rubber is partiall or wholl denerved,which quality can be detected y pulling a piece of milled rubber apartbetween the lingers and observing the manner in which it separates, thedenerving of the rubber be ing sufficiently complete when it pulls apartwithout the appearance of any lumps in the attenuated portions.Thebroken down sheets are then removed from the mill and the guayulerubber is placed on the mill and warmed by working. The broken downsheets are then added to the gua ule rubber and then the mono-chloro-napthaline is added, and the mixture milled until it has a uniformconsistency and color. The zinc oxide and the sulphur are then added andmixed until they are uniformly distributed throughout the mass. It willbe noted that the materials above mentioned are brought into thesemisolid plastic condition Without the use of volatile solvent, such asare employed in making so-called rubber solutions or cements. Themono-chloro-naphthaline is an oily material not volatile, the additionofiwhich facilitates the softening and work ing ofthe rubber withoutinjuring its qualit y or burning it, which might otherwise result unlessthe operations were most carefully watched, to prevent undue heat.

The compound is then transferred to a warming mill preparatory tofeeding the calender upon which the compound is to be forced into theunwoven fibrous fabric. The mixing mill and calender maybe machines ofstandard approved types as used extensively in the rubber industry, inthe manufacture of friction tire fabrics. Such a calender is illustratedin Fig. 1 of the drawing, in which 1, 2 and 3, represent a verticalseries of three rollers provided internally with independent heatingmeans which may be of any usual or desired character, and in thisinstance is indicated as a heating coil arranged within each of saidrollers, said coils bein indicated by the numerals 4, 5 and 6, whic areconnect'ed with pipes 7, 8 and 9 respectively, passing through thesupporting trunnions of the rollers. The central roller, 2, is supportedin stationary bearings and the up er and lower rollers 1 and 3 invertically ad ustable bearings provided with any desired type ofadjusting means by which variable pressure may be a plied. In thisinstance the bearings for t 'e rollers 1 and 3, indicated at 10 and 11respectively, are shown as provided with adjusting screw shafts 12 and13 respectively, which canbe operated by hand wheels,

. or in any other desired manner. The rollers 1, 2 and 3 are providedwith means for regulating independently the temperature of each, whichtemperature adjusting means can be of any usual or desired character. Inthe present instance we have shown a steam pipe, indicated at 14, and acold water within the rollers, and each of the branch pipes is providedwith an inde endent controlling valve. The branch plpes for the roller 1are indicated at 16 and 17, 'and the valves therefor, at 18 and 19respectively.

The branch pipes for the roller, 2, are indicated at 20 and 21, and thevalves therefor, at 22 and 23 respectively. The branch pipes for theroller, 3, are indicated at 24 and 25, and the valves therefor, at 26and 27 respectively. The rollers are so geared that the center rollermoves at a considerably faster speed than the others. The differentialin speed of the center roller which We have found most suitable for thematerial given above is that of about three to one.

The calender is provided with the -usual feeding and rollingup devices(not shown) for the fabric. In treatin the fabric, the binding compound,in the orm of a dough like or putty likesemi-solid and plastic at thetime of application, is applied from the warming mill to the calenderbetween the top roller, 1, and the central roller, 2, as shown at 28.The temperatures of the various rollers are adjusted so that the mixed,milled compound adheres in a thin sheet to the central roller and doesnot adhere to the top roller. The bottom roller is well heated with drysteam to the desired. temperature. A few small strips of the cotton feltor other fibrous material to be treated, in which the fibres are inamore or less loosely associated condition, are first thoroughly dried,and are then passed through the calender between the central roller, 2,and lower roller, 3, with such adjustments of the upper and bottomrollers that the binding material is pressed into the fabric so as touniformly coat the fibres without completely filling the interfibrespaces and leaving the fibres united by the cohesion of their individualcoatings at their points of contact and intersection. The pressure ofthe rollers compresses the fibres beyond the point at which they will beheld by the binding compound in its then plastlc condition, and thebinding material is forced into the fabric, as above described so as tosubstantially uniformly coat the fibres. When the pressure is relievedas the fabric leaves the calender rolls, the fibres exp and somewhat bytheir inherent elasticityfid form interfibre spaces between thecoatings,

ings. This will, of course, depend somewhat upon the weight andcompactness of the fibrous material used. Where a cotton felt having aweight of four and a half ounces per s uare yard is employed, anadjustment of t e top and bottom rollers with respect to the centralroller, so that a bank of the binding material is formed over the feltas it is enterin between the center and top rollers with a ank thicknessof from one eighth to one quarter of an inch, is found to give very goodresults. After the proper ad uStment of the calender has been determinedby the use of strips or pieces of the fabric, so as to secure thedesired result, a continuous length of the unwoven fabric is drawn froma roll and passed through the calender. The supply of binding materialis maintained b periodic additions of the prepare material from thewarming mill. Th 'eight of the finished goods is about twe eounces persquare yard. Where, for operating purposes, it is not desired tomaintain the calender at such accurate adjustments, or where extra heavygoods are run, the goods may be passed through 'on one side and thebinding material forced somewhat past the middle point, and then runthrough on the opposite side to complete the coating of the fibres andtheir union by the cohesion of their coatings, without complete- 1yfilling the interfibre spaces.

As the fabric leaves the roller, 2, on the side opposite that from whichit enters, the separation of the fabric from the layer of bindingmaterial, 29', on the roller, 2, leaves the surface of the fabricadjacent to the roller, 2, slightly roughened, and the'binding materialbeing slightly tacky, any loose fibres on the surface, which are ofcourse thoroughly coated, will be left in a more or less vertical.position, perpendicular to the surface of the fabric, as indicateddiagrammatically in Figs. .3 and 4, and these upstanding coated fibreswill form bonds for" firmly uniting to the fabric subseqgently anysurface coating which it may e desired to apply thereto, as where thefabric is employed as a base fabric in the manufacture'of artificialleather and the like. Fig. 3 is a diagrammatic representation of thefabric as produced where the operation is so conducted that the bindingmaterial is caused to uniformly coat all the fibres throughout the'material in a single pass or operation. The surface adjacent to theroller, 2, is indicated as a roughened surface, at 32, and theupstanding coated fibresare diagrammatically indicated at 33. Fig. 4 isa similar'diagrammatic sectional view illustrating the fabric after ithas been treated 'under conditions of speed and pressure, such that thebinding material is caused to coat the fibres substantially .half waythrough the thickness of the fabric, theroughened surface adjacent tothe roller, 2, being indicated at 34, and the upstandin fibres at 35.Where the process is carrie out in'this manner, the fabric is reversedand given another pass through the same or another similar apparatus, soas to force the binding material Into the reverse side of the fabric,and coat the fibres of the remaining portion, in which case theroughened surface, 3-1, and upstanding fibres, 35, of the previouslycoated surface, will be rolled down by contact with the smooth roller,3, and the last treated side of the fabric will be left with a roughenedsurface and u)- standing fibres, as indicated in Fig. 3. f it is desiredto have the fabric perfectly smooth on both sides, this can be readilyaccomplished by passing the fabric through a pair of plain rollers toroll down the roughened surface and upstanding fibres on the face lasttreated, leaving the fabric in the cFondition illustrateddiagrammatically in In Fig. 2 we have illustrated diagrammatically,apparatus for treating the fabric on both sides by continuous operation.In this instance the fabric is first passed through an apparatus of thekind described, comprising rollers, 1, 2, 3, for the purpose of coatingthe fibres substantially half the thickness of the material, after whichit is turned and passed between the proper rollers of another series of'rollers, 1, 2 and 3, constructed ,and operated in the same manner ashereinbefore described, the fabllC being turned in an usual manner, asby means of vertical gui ing rollers, indicated at 36. Where it isdesired to have the fabric entirely smooth on both sides, the fabric,indicated at 31, may be passed between plain rollers 37 and 38, asindicated in Fig. 2, to roll down the face last treated, and leave thefabric in the condition indicated in Fig. 5, but where a surface coatingof any kind is to,be applied to the fabric, it will be found distinctlyadvantageous to use it in the form indicated in Fig. 3.

The goods may be cured in rolls between sheeting upon drums in anautoclave at the following cure fifteen minutes at ten pounds open steampressure, and an hour and a quarter at twenty pounds open steampressure. When cured in the press, the goods should be cured for thirtyfive minutes at fifty pounds steam pressure in the steam jacket. Theforegoing example states only one 'of a number of compounds which may beutilized in carrying our process into effect. With other compoundscontainin other gradesof rubber than those mentione above, along withasphaltum, mineral rubber substitute, Burgundy p tch, pasty substitute,brown and white factice, with various mineral fillers, such as litharge,whitin barytes, antimony sulphide, sienna, an

Ill

other inorganic and organic accelerators and dispersing agents,variations, in the calenden adjustments and cure will be required inline with general practice in the handling of'such compounds as may beconstructed.

It is obvious that by varying the composition of the binding material, awide range of properties of the resulting fabric can be obtained. I

The application of the binding material in dough like semi-solidcondition by the aid of pressure, in the manner described, compressesthe fibres so as to drive out the occluded air and permit the bindingmaterial to penetrate thoroughly and thoroughly coat the fibres throughthe entire thickness of the fibrous material treated. As the pressure isreli ved, there will ordinarily be a slight exgh-dsion of the fibrousmaterial, due to the re iliency of the fibres. This causes the coatedfibres to adjust themselves and separate slightly, but leaves themconnected by the cohesion of their coatings at separated points,accumulations or agglomerations of the binding material resulting attheir various intersections or points of contact, and frequentladditional bonds extend between the fi re coatings, which are plainlyvisible under the microscope, and when the resulting fabric has beenhardened, cured or vulcanized, as the case may be, a fabric of greattensile strength results. Thus, in Fig. 6, which illustrates a number offibres taken from the central portion of our improved fabric andmagnified, 40, rep-'- resents the fibres, 4 1, the coatings thereof,connected at points of intersection and contact, as at 42, by thecohesion of the fibre coatings and 43, represent additional bonds of thebinding material connecting the coatings of individual fibres.

An examination of ourimproved fabric under a microscope shows it to havean almost uniform. uasi-crystalline appearance,

- all of the fibres eing thoroughly coated and bound together b thecohesion of their coatings, and by bon s connecting the fibre coatings,without filling completely theinterfibre 3 aces, thus forming minute andsubstantia' lly. uniform interstices between the coatings of the fibresat point-s between the intersections and points of contact of said fibrecoatings, and between said bonds.

. throughout the material. Our fabric, therefore, is clearlydistinguished from fabrics in which fibrous material is incorporated ina solid "mass of rubber or other plastic produced by mixing andvulcanizing rubber or like material and causing it to solidify throughand around the incorporated fibres or otherwise. In contra-distinctionto this t pe of fabric our 'improvedfabric is'actul rvious'to air anddry gases and is. ne as rily much lighter and more flexible than thosefabrics .in which a solid body of colloidal material surroundsincorporated fibres. At the same time our improved fabric, whilepervious as before stated, to air and dry gases, is substantiallyimpervious to water and many other liquids and is timetically waterprooWe understand this apparent contradiction to be due to the fact that thefibres of our improved fabric are thoroughly and individually coatedwith the binding material so that they cannot absorb water, and theapertures or interstices between the adjacent fibre coatings are sominute and the repellent action of the binding material of the fibrecoatings to water is so great that the water remains on the surface insomewhat the same manner as quicksilver will remain for the same reasonon the surface of a piece of chamois leather, which air and dry gas willreadily penetrate. A sheet of our improved fabric has been suspendedhorizontally and the convex portion filled with water and permitted toremain for ten or twelve hours without apparent absorption of Water intoor penetration of water through the fabric. It will be readilyunderstood that this peculiar and novel characteristic of our improvedfabric fits it admirably, for purposes of clothing, on account of itsextreme lightness and fiexiblity, its

water-proofness and its ventilating or breathing qualities. Anotherhighly important feature of our new fabric is that when rubber is usedas the binding material,

it is elastic or yielding in all directions due acteristic of our newfabric makes it particularly desirable as a substitute for leather or asa base fabric for leather substitutes. Cushions and other upholsterycovered with our fabric will yield to pressure and reassume theiroriginal form without producing wrinkles which are soon formed in theordinary leather substitutes, which, not being elastic, are soonstretched so as to produce a sa or'looseness in the coverings. Our newabric can be used with great advantage for waterproof clothing; for theuppers as well as for the soles and heels of shoes (in the case of solesand heels a number of superimposed layers of the fabric being employedand consolidated by the binding material), in all of which its elasticcharacter is desirable, as well as for tarpaulins tents, boat covers,and all .purposes where a light and waterproof material is desired.

It also forms an admirable substitute for leather, and if desired, canreadily be made entirely impervious, either b subjecting it to greatpressure, or by t e application thereto of any of the usual or preferredtypes of coatings, such as varnish, the usual cellulose hitrate andcellulose acetate coating compositions, for example, or any otherpreferred coating compositions.

If a denser or heavier fabric is desired, we can readily produce thesame by adding to the dough like or putty like rubber compound. or otherbinding material used, a desired preparation of solid insolublematerial, such as, for example, oxide of zinc, whiting, magnesium oxide,sulphur oxide, and various coloring compounds, antimony sulphide, oxidesof iron, gas black or lamp black, and various pigments which can beforced mechanically, as before described, into the interior of thefabric with and after having been thoroughly incorporated in the doughlike binding material, thereby imparting any desired degree of density,thickness, weight, shade or color to the resulting fabric uniformlythroughout the thickness thereof.

Our fabric can also be made denser and substantially, and in some cases,wholly impervious, by subjecting it to great pressure sufiicient toforce the fibre coatings and fibres together and substantially close theinterstices or interfibre spaces which would otherwise exist. This maybe accomplished by subjecting a single sheet or a series of superimposedsheets, united by a rubber compound or other binding material, orcement, to great pressure, as in a hydraulic press, and such highlycompressed material may or may not be vulcanized, as desired. Shoe solesand heels can be formed in any desired thickness in this manner, andwould be impervious, and at the same time both flexible, and to anextent elastic, although not so elastic as the material formed withoutthe use of this increased pressure treatment. Belting and straps canalso be formed in this way, also floor coverings and like sheetmaterials.

' Our improved fabric can be given any desired color either by mixingpigments with the binding material, or otherwise. It can be used eitherwith or without a surface coatin for book covers and many other uses were leather or imitation leather is now employed, and its elasticcharacter adapts it espscially for such purposes, and for upho tery,automobile tops, etc., where it is stretched over unelastic surfaces orframes.

In the preparation of our improved fabric it may or may not bevulcanized after treatment, as before described. With the bindingmaterial such as described, we prefer to subject it to a drying, curingor vulcanizing action by any of the well known methods for treating suchmaterials, such for example, as the festooning method, the curingchamber method, the autoclave method, or any other desired manner forthe purposes of drying, curing or vulcanizing it.

iVhile our improved "fabric is substan-' tially impervious to water inthat it will not permit the passage of water therethrough, nor will thecoated fibres absorb water, we have found that a slight amount ofmoisture may be deposited in the interstices or interfibre spacesadjacent to the face of the fabric, especially if the fabric issubjected to pressure. For example, we have found by experiment that ournew fabric is peculiarly suitable for use for the sweat bands of hats,and is much more desirable than a glazed imitation leather. When soused, the moisture of perspiration, instead of running down the band,upon the forehead, is held in the surface interstices of the fabric, andwhen the hat is removed, the moisture quickly evaporates on account ofthe permeability of the material to dry air. Where an elastic materialis desired, the material is preferably vulcanized in such manner as toconvert the binding material from the plastic to the elastic condition,and impart the desired degree of elasticity to the finished material.

We are of course aware of the fact that oalenders have been used forapplying surface and so-called friction coatings to woven fabrics, andthat in some instances the material of such surface coatings has beencaused to enter between the crossed warp and weft threads, insubstantially the same manner that plaster is pressed through supportinglaths. In such instances, however, there is no coating of the fibres ofthe material, and on cutting such a material, the fibres of which thethreads are composed will be found to be in their natural condition andthe interior fibres uncoated and out of contact with the coatingmaterial. We beleive that we are the first to apply to a fabric in.which the fibres are in a more or less loosely associated relation, abinding material in a semi-solid condition and plastic at the time of aplication, which we have referred to as a dough like or putty likecondition, so as to cause it to coat the fibres without fillingcompletely the interfibre spaces and leaving the individual fibresconnected by the cohesion of their coatin s at points of contact andintersection, an we believe ourselves to be the first to apply a bindingmaterial to a non-woven fabric by means of a calender. It is extremelyimportant thatthe bindin material be in the proper condition in or erthat it may be caused to penetrate into the fabric and coat theindividual fibres in the manner described. The composition must have ahigh degree of cohesion and also a high degree of adhesion,

so that while it tends to cling to itself, it will also cling around andcoat the individual fibres. The condition of the binding mate rial maybe aptly described as being substantlally that of a rubber base chewinggum which has been chewed at the temperature the onl method ofimpregnation heretofore.

eifecte It has heretofore been considered impossible to impregnate anunwoven fabric in any other way than by the Wet process, and we havedemonstrated that this can be successfully accomplished by our improvedprocess. proved fabric after impregnation in the manner described hereinis from 1% to 3 times that of the original fabric, and the process maybe carried out by a single pass of the material through the roll, or ifpreferred, by not more than two passes.

. We are aware of the fact that woven fabrics have been coated orfrictioned with binding material, which is applied by means of acalender, but these processes have no bearing whatever on our process,and there is not the slightest resemblance between our improved fabric.and-the coated and frictioned woven fabrics produced by the oldcalendering methods. In the case of coatings, the coating material isusually applied in a very thin, almost liquid condition, and spread uponthe surface of the woven fabric. In the case of friction tire fabric andthe like, and in the manufacture of linoleums, the plastic material usedis pressed upon the woven fabric. and will naturally extend into orthrough the orifices between the warp and weft threads, but this isentirely different from our process, as the plastic used in suchfrictioning and calendering processes merely extends part way around thetwisted threads without penetrating into the interior thereof andwithouticoating the individual fibres of the fabric at all.

What we claim and desire to' secure by Letters Patent is 1. The hereindescribed process, which consists in applying to a fabric composedofunspun unwoven natural fibres, ,a binding material in the form of adough like semisolid plastic at the time of application, having suchhigh cohesiveness and adhesiveness as to be capable of penetratingaround and betweenthe natural fibres, and forcin said binding materialby pressure into the abric and around and upon the individual fibres soas to coat the individual fibres throughout the fabric withoutcompletely filling the interfibre spaces and causmg the fibres to adhereat points of contact and intersection The increase in weight of our in1-by the cohesion 'of their individual coatings.

2, The herein described process, which consists in applying to a fabriccomposed of unspun unwoven natural fibres, a binding material in theform of, a dough-like semi solid and plastic at the time of application,

having suchhigh cohesiveness and adhesiveness as to be capable 6fpenetratin around and between the natural fibres, an forcing 'saidbinding material by pressure into the 'fabric and around and upon theindividual fibres so as to coat the' individual fibres throughout thefabric without completely filling the interfibre spaces and causing thefibres to adhere at points of contact and intersection by the cohesionof their individual coatings, and treating the resulting fabric so as toconvert the bindingmaterial into an elastic material. H

3. The herein described process, which consists in applying to a fabriccomposedof unspun unwoven natural fibres, a vulcanizable binding,material in the form of a dough like semi-solid plastic at the time ofapplication, and having such high cohesiveness and adhesiven'es's as tobe capable of penetrating around and between the natural fibres, anforcing said binding material by pressure into the fabric and around and'upon the individual fibres so as to coat the individual,

fibres throughout the fabric without com-' pletely filling theinterfibre spaces 'and causing the fibres to adhere at points of contactand intersection by the cohesion of theirindividual coatings, andvulcanizing the resultin fabric so as to change the binding materialfrom the plastic to an elastic consurface with pressure to a fabriccomposed of unspun unwoven fibres and forcing portions of said coatingor binding material into the fabric and around and upon the individualfibres throughout the fabric, so as to coat the individual fibreswithout filling the interfibre' spaces, and separating the impregnatedfabric from the coated rotary surface so as to leave the adjacentsurface of the fabric roughened, and portions of the surface fibrescoated and upstanding so as to form bonds for a subsequent exteriorcoatin 5. 'I he herein described process, which consists in applying toa "rotary surface, a

binding material in the form of a dough like semi-solid of such highcohesiveness and ads hesiveness as. to be capable of penetrating aroundand between the natural fibres of the material to be treated, applyingsaid coated surface with pressure to a fabric. composed of unspununwoven fibres and forcing portions of said coating or binding materialinto the fabric and around and upon the individual fibres throughout thefabric, so as to coat the individual fibres without filling theinterfibre spaces, and separating the impregnated fabric from the coatedrotary surface so as to leave the adjacent surface of the fabricroughened, and portions of the surface fibres coated and upstanding soas to form bonds for a subsequent exterior coating, treating .theopposite face of the fabric in like manner by means of a rotary surfacecoated with the binding material, and simultaneously treating theroughened previously treated surface of the fabric with pressure by arotary surface free from binding material, to roll down the upstandingfibres and smooth the roughened surface thereof.

6. The herein described process, which consists in applying to a rollerof a calender an adhesive coating of binding material comprising arubber base plastic at the time of application, and made plastic bymilling, and passing between said coated roller and an opposed roller,an unwoven fabric composed of unwoven unspun fibres to units said fibresin said fabric.

7 The herein described process which .con-

sul hur, and rendered plastic by milling wit out the addition ofvolatile liquid solvents, and passing between said coated roller and anopposed roller an unwoven fabric composed of unwoven, unspun fibres, tounite the fibresin the fabric, and then vulcanizing the fabric.

8. The herein described process which consists in coating a roller of acalender with binding material plastic at the time of application havinga rubber base mixedwith sulphur and filling material, and renderedplastic by milling, and passing between said coated roller, and an oposed roller, under pressure, a non-woven abric composed of unspun fibresto unite the fibres in the fabric and carry the filling material withthe other components of the binding material into the fabric.

9. The herein described process which consists in calendering an unwovenfabric composed of unspun fibres with a binding material in semi-solidform and plastic at the time of application, consisting of rubber mixedwith sulphur and brought into plastic condition by milling, without theuse of volatile solvents, to force said plastic binding material intothe interfibre spaces of the plastic, and coat the fibres withoutcompletely filling the interfibre spaces.

In testimony whereof we ailix our signatures.

HERMAN E. BROW'N. JORDAN HOMER STOVER.

